Negative working photoresists containing photoinsolubilizable polymers are known to be useful in a variety of applications. Such compositions can be coated on a support and imagewise exposed so as to crosslink, harden or otherwise render insoluble the exposed coating. A wash or developing step removes the unexposed coating. Such compositions are sometimes referred to as being of the "wash off" type.
Photohardenable dyeable "wash off" compositions are known. One dyeable wash off composition known in the art is dichromated gelatin. In this approach, gelatin is employed in combination with a dichromate salt employed as the radiation responsive hardening agent. Gelatin is known to exhibit some capacity for mordanting dyes.
Another dyeable wash off composition is described in U.S. Pat. No. 4,220,700. In this approach, a diazo resin can be mixed with certain mordants to produce photohardenable imaging compositions and elements useful in the preparation of continuous tone dye images.
Problems exist with both diazo resin/mordant and dichromated gelatin resist materials. For example, dichromated gelatin layers exhibit dye saturation levels which vary widely with PH, temperature and the amount of exposure. On the other hand, diazo resin/mordant resists exhibit less variable dye saturation levels and better resolution and solution keeping properties compared to dichromated gelatin. However, the diazo resin/mordant resist is inherently slow and tends to discolor upon exposure to heat or light in the presence of oxygen. Moreover, both of these dyeable resist materials are highly colored (yellow brown) and absorb blue light, which is particularly disadvantageous in some applications, for example, in the manufacture of color filter elements for some solid state image sensors.